Fig 1.
Location of the Maestrazgo Basin and its seven sub-basins (A) based on Aurell et al. [45]. The studied locations are indicated by coloured stars (San Just, SJ; Arroyo de la Pascueta, AP; Cortes de Arenoso, CA). (B) Detail of the geological map with the location of San Just (SJ) section in the Las Parras Sub-basin. Based on data from the geological map of Spain Magna 1:50000 [46]. (C) Detail of the geological map showing the location of Arroyo de la Pascueta (AP) and Cortes de Arenoso (CA) sections. Based on data from the geological map of Spain Magna 1:50000 [47].
Fig 2.
Synthetic stratigraphic log of the Maestrazgo Basin from the Triassic to the Upper Cretaceous.
(A) The red arrow shows the location of the Utrillas Group in grey colour. Based on data from [52, 55]. (B) Detail of the lithostratigraphy of the studied succession, where the Utrillas Group Erg System overlies the coal-bearing deposits of the Escucha Formation with a regional unconformity surface (RUS), which marks the onset of the Erg System. The Utrillas Group succession is, in turn, overlain by marine carbonate deposits of Mosqueruela Formation. Based on data from [59].
Fig 3.
Stratigraphic log of the upper Albian San Just outcrop (SJ), showing the distribution of selected biostratigraphically relevant palynomorphs.
The San Just amber outcrop is at the top of the level 3. Red dots: location of the collected samples. Black dots: stratigraphic distribution of the selected taxa. Ø: barren sample.
Fig 4.
Amber from the late Albian San Just outcrop (Utrillas, Teruel) and its bioinclusions.
(A) Big kidney-shaped amber mass of 640 g. (B) Unearthed amber pieces. (C) Undetermined Lagonomegopidae? spider (SJNB2012-12-07). (D) Holotype of Actenobius magneoculus (Coleoptera, Ptinidae) (MAP-7727). (E) Holotype of Cretevania alcalai (Hymenoptera, Evaniidae) (CPT-960). (F) Avian dinosaur feather barb close to an undetermined Platygastroidea wasp (CPT-4078 and CPT-4079, respectively). Scale bars C–F, 0.5 mm. Images A and B are provided by Enrique Peñalver. Acronyms SJNB, CPT and MAP correspond to amber pieces housed at the Museo Aragonés de Paleontología (Fundación Conjunto Paleontológico de Teruel-Dinópolis) in Teruel, Spain.
Fig 5.
Stratigraphic log of the upper Albian/lower Cenomanian Cortes de Arenoso section (CA), showing the distribution of selected biostratigraphically relevant miospores (see the legend in Fig 3).
The La Hoya amber outcrop is at the top of the section (level 35). Red dots: location of the collected samples. Black dots: stratigraphic distribution of the selected taxa. Ø: barren samples.
Fig 6.
Stratigraphic log of the upper Albian Arroyo de la Pascueta section (AP), showing the distribution of selected biostratigraphically relevant miospores (see the legend in Fig 3).
The Arroyo de la Pascueta amber outcrop is at the top of the section (level 34). Red dots: location of the collected samples. Black dots: stratigraphic distribution of the selected taxa. Ø: barren samples.
Table 1.
List ordered alphabetically of the palaeobotanical taxa considering their botanical affinities, and possible preferred environment which are based in bibliographic references for aquatic palynomorphs [71, 72], ferns and allied [73–76], gymnosperms [12, 24, 74, 77–91] and angiosperms [12, 92–99].
Table 2.
List of arthropod taxa as bioinclusions identified from San Just, Arroyo de la Pascueta and La Hoya Cretaceous amber-bearing outcrops with information about autoecology of each species and possible preferred environment.
Fig 7.
Light photomicrographs of selected aquatic palynomorphs and gymnosperm pollen grains.
(A) Botryococcus braunii, level AP-34.1. (B) Chomotriletes minor, level AP-34.1. (C) Cribroperidinium sp., level AP-10.1. (D) Ginginodinium cf. evittii, level SJ-2.1. (E) Tenua hystrix, level SJ-2.1. (F) Odontochitina rhakodes, level SJ-3.1. (G) Oligosphaeridium complex, level SJ-2.1. (H) Kiokansium unituberculatum, level AP-13-1. (I) Cycadopites sp., level SJ-3.7. (J) Afropollis jardinus, level CA-5.2. (K) Inaperturopollenites dubius, level SJ-2.1. (L) Uesuguipollenites callosus, level AP-6. (M) Callialasporites segmentatus, level AP-6. (N) Callialasporites trilobatus, level AP-13.2. (O) Gnetaceaepollenites oreadis, level AP-16.2. (P) Exesipollenites tumulus, level SJ-2.1. (Q) Tetrad of Classopollis major, level SJ-2.3. (R) Parvisaccites radiatus, level AP-4.3. (S) Vitreisporites pallidus, level SJ-2.2. (T) Podocarpidites sp., level AP-25.6. Specimens A–C, H, L–O, R, T are from the Arroyo de la Pascueta section; specimens D–G, I, K, P–Q, S are from the San Just section; the specimen J was found in a sample from the Cortes de Arenoso section. Scale bar equals 20 μm except in S when it equals 10 μm.
Fig 8.
Light photomicrographs of selected spores of Bryophyta and Pteridophyta.
(A) Reticulosporis gallicus, level CA-21.03. (B) Cyathidites australis, level SJ-2.1. (C) Polypodiisporonites cenomanianus, level CA-35.01. (D) Verrucosisporites sp., level AP-25.6. (E) Concavissimisporites cf. crassatus, level SJ-3.6. (F) Gregussisporites orientalis, level SJ-5.2. (G) Contignisporites cooksoniae, level AP-25.9. (H) Staplinisporites caminus, level AP-25.6. (I) Densoisporites velatus, level CA-2. (J) Foveosporites cf. parviretus, level AP-25.7. (K) Cibotiumspora juriensis, level CA-5.1. (L) Taurocusporites segmentatus, level SJ-3.1. (M–N) Cicatricosisporites proxiradiatus, level CA-21.04, (M) proximal side, (N) distal side. (O–P) Cicatricosisporites potomacensis, level AP-25.7, (O) proximal side, (P) distal side. (Q) Nodosisporites segmentus, sample AP-25.7. (R) Appendicisporites cf. crenimurus, level CA-10.01. (S) Appendicisporites tricornitatus, level AP-4.3. (T) Patellasporites tavaredensis, level SJ-5.2. Specimens A, C, I, K, M–N, R are from Cortes de Arenoso section; specimens B, E–F, L, T are from San Just section; specimens D, G, H, J, O–Q, S are from Arroyo de la Pascueta section. Scale bar equals 20 μm except in H when it equals 10 μm.
Fig 9.
Light photomicrographs of selected pollen grains of angiosperms.
(A) Asteropollis asteroides, level CA-2. (B) Jusinghipollis cf. ticoensis, level AP-10.2. (C) Clavatipollenites tenellis, level AP-32.3. (D) Stellatopollis cf. barghoornii, level SJ-5.2. (E) Pennipollis reticulatus, level CA-4. (F) Liliacidites cf. clavatus, level CA-14.01. (G) Dichastopollenites sp, level SJ-3.5. (H–I) Dichastopollenites dunveganensis, (H) level CA-7, (I) level SJ-3.8. (J) Doyleipollenites robbinsiae, level SJ-2.2. (K) Retimonocolpites dividuus, level AP-25.2. (L) Dichastopollenites cf. reticulatus, level AP-25.6. (M) Liliacidites tectatus, sample AP-25.7. (N) Tucanopollis crisopolensis, level CA-3.2. (O) Transitoripollis sp., level AP-25.6. (P) Rousea georgensis, level SJ-3.8. (Q) Phimopollenites pannosus, level SJ-3.7. (R) Tricolpites nemejci, level AP-10.2. (S–T) Dryadopollis vestalis, (S) specimen in polar view, level AP-10.2, (T) specimen in equatorial view, level CA-14-01. (U) Phimopollenites pseudocheros, level AP-34.2. (V–W) Tricolpites cf. maximus, (V) specimen in polar view, level CA-3.1, (W) specimen in equatorial view, level CA-3.1. (X) Hammenia fredericksburgensis, level SJ-3.4. (Y) Echinipollis cenomanensis, level CA-35.01. (Z) Penetetrapites mollis, level CA-1. (AA) Hammenia fredericksburgensis, level CA-35.01. (AB) Artiopollis praecox, level AP-25.2. (AC) Senectotetradites sp., level AP-10.2. (AD) Senectotetradites grossus, level CA-35.01. Specimens A, E–F, H, N, V–W, Y–AA, AD are from Cortes de Arenoso section; specimens B–C, K–M, O, R–S, U, AB–AC are from Arroyo de la Pascueta section; specimens D, G, I–J, P–Q, T, X are from San Just section. Scale bar equals 10 μm.
Fig 10.
Principal Component Analysis (PCA) performed with the most relevant identified taxa and levels.
(A) Classopollis spp. (B) Exesipollenites tumulus. (C) Araucariaceae. (D) Patellasporites tavaredensis. (E) Cicatricosisporites spp. (F) Crassipollis chaloneri. (G) Clavatipollenites spp. (H) Plicifera spp. (I) Cyathidites/Deltoidospora. (J) Gleicheniidites senonicus. (K) Monosulcites spp. (L) Eucommiidites sp. (M) Pennipollis spp. (N) Peromonolites allenensis. (O) Tucanopollis spp. (P) Marine protists. (Q) Inaperturopollenites dubius.
Fig 11.
Selected plant macro and mesofossils from the El Maestrazgo Basin.
(A) Leaf of Nehvizdya (= Eretmophyllum) penalveri, No. K 2788. (B) Shoot of Frenelopsis turolensis, No. K 2786. (C) Fragment of leaf of Dammarites cf. albens, No. K 2789. (D) Ramified shoot of Frenelopsis cf. turolensis, No. K 2797. (E) Shoot of Frenelopsis justae, No. K 2806. (F) Fruit fragment of Montsechia-type with orthotropous seed (Spermatites), No. K 2795. (G) Fragments of leaves of Mirovia gothanii, Nos. K 2807–2811. (H) Angiosperm fruit of cf. Serialis sp., SEM image, No. K 2803. (I) Shoot fragment of Brachyphyllum cf. obesum, SEM image, No. K 2804. (J) Shoot fragment of Widdringtonites sp., SEM image, No. K 2805. (K) Basal part of a leaf of Nehvizdya (= Eretmophyllum) penalveri, No. K 2794. Specimens A–C, G are from Arroyo de la Pascueta section; specimens D, F, K are from Cortes de Arenoso section; specimens E, H–J are from San Just section. Scale bars: A–D = 10 mm; E, G, K = 5 mm; F, H–J = 1 mm.
Fig 12.
Detailed palynological chart for San Just section (SJ).
Blue colour: marine palynomorphs; yellow colour: spores of ferns and allied; green colour: Gymnosperm pollen; red colour: Angiosperm pollen.
Fig 13.
Detailed palynological chart for Cortes de Arenoso section (CA).
Blue colour: marine palynomorphs; yellow colour: spores of ferns and allied; green colour: Gymnosperm pollen; red colour: Angiosperm pollen. 1. spike due to the abundance of Tucanopollis spp. 2. spike due to the abundance of “Liliacidites” minutus.
Fig 14.
Detailed palynological chart for Arroyo de la Pascueta section (AP).
Blue colour: marine palynomorphs; yellow colour: spores of ferns and allied; green colour: Gymnosperm pollen; red colour: Angiosperm pollen.
Fig 15.
Composite range chart showing selected species of biostratigraphic interest identified in the Lower Cretaceous sections from the Maestrazgo Basin.
L = lower; M = middle; U = upper.
Fig 16.
Schematic model of the late Albian fore-erg setting, including the types of vegetation and their distribution in the different sub-environments.
Fig 17.
Conceptual palaeoartistic reconstruction of the late Albian wet interdunes in the fore-erg from the Maestrazgo Basin (eastern Spain).
This environment developed near the Tethys, where (A) coastal forests with Araucariaceae grew. The riparian places of the wet interdunes (oasis) (B) were covered by fern and angiosperm vegetation. (C) Fresh water/brackish aquatic angiosperms inhabited wet interdunes. (D–E) Xerophytic plant community involving Cheirolepidiaceae, Cupressaceae (D) and other gymnosperms groups such as Bennettitales, Cycadales (Monosulcites/Cycadopites-producers) and Gnetales (Equisetosporites-producers) (E) that integrated arid woodlands.